Information communicated along a network is commonly referred to as a data packet. A data packet is described as a well-defined block of bytes, typically consisting of a header, data, and trailer. The header of a data packet usually includes the source and destination addresses.
In the large scale networks, switching hubs are provided to "switch" data packets from one network segment to another network segment. These network segments may be separated by several intervening networks and, possibly, by many miles.
Typically, switching hubs receive data packets on a port coupled to a network segment, internally processes the data packet, and the transmit the data packets out a port coupled to a different network segment.
In some cases, more advanced switching hubs are able to increase the speed and efficiency of transferring data packets by performing packet switching techniques which involve relaying the packets through different switching hubs along the best routes presently available between the source and the destination. Determining the route upon which the packets are sent can be based upon such factors as the traffic of the available routes and which routes are presently operative.
Typically, the switching hubs operate at the network layer of the seven layer Open Systems Interconnection (OSI) Reference Model developed by the International Standardization Organization (ISO). Moreover, considering that switching hubs are independent of the data-link layer protocols, switching hubs can typically connect networks using different architecture (for example, Ethernet to Token Ring or Ethernet to FDDI).
However, as the bandwidth of network transmission mediums continuously increases, the speed and efficiency of the switching hubs should be increased to avoid slowing down the transmission of the data along the networks.